The most quietly devastating song I heard last year was the one where Jason Isbell starts to come to terms with the idea of death, the one thing that can tear him away from his life. “Maybe we’ll get 40 years together, but one day I’ll be gone, or one day you’ll be gone,” Isbell laments on “If We Were Vampires,” my favorite song from last year’s The Nashville Sound. In close harmony, Isbell’s wife, Amanda Shires, sings those exact same words. They’re singing to each other, about each other, and it knocks me out every time.

Shires doesn’t have any moments quite like that on To The Sunset, her own new album, and that’s probably for the best. The closest she comes is on “Parking Lot Pirouette,” the album’s first song. Over a slow and soulful organ groove, with her voice bathed in echo, Shires sings about trying, and failing, to walk away from someone: “Last night, you walked me to my car / You said, ‘You won’t be getting far before you turn around’ / I did a parking lot pirouette / I said, ‘You’re right, I’m not done with you yet.'” It’s just as nakedly romantic, and yet it’s completely different. It’s a quick snatch of a moment, a fleeting release. And moments like that are the ones where Shires shines.

For the past few years, Shires has existed a bit in the shadow of her husband. It’s just one of those things. Isbell’s had a long road, from the Drive-By Truckers to addiction to recovery. But recently, he’s emerged as one of the biggest stars, and the best songwriters, in this whole roots-rock constellation. Isbell wouldn’t have had that career turnaround without Shires. He beat addiction because of Shires, and the two have a family now. He wrote “Cover Me Up,” maybe his best-loved song, for her. In recent years, she’s played as a member of the 400 Unit, Isbell’s backing band, though she still takes days off. (When I saw Isbell in Charlottesville last year, Shires wasn’t there; she was in Europe with John Prine.)

Shires has had a long road of her own. As a teenage Texan fiddle prodigy, she joined the Texas Playboys, the decades-old Western swing institution that had once backed Bob Wills. Later on, she got an MFA in creative writing. (If you were building an Americana songwriter from scratch, you probably couldn’t come up with a better background than that.) Shires’ solo career goes back more than a decade; she was cranking out albums long before she met Isbell. And on To The Sunset, it’s Isbell’s turn to be the supporting player. He plays guitar on every song on the album. Dave Cobb, the album’s producer, is the guy who helped establish the recent-vintage big-tent country-rock sound, working with artists like Chris Stapleton, Sturgill Simpson, and on Isbell’s own last three albums. Cobb’s a supporting player on this one, too. He plays bass.

Those two anchor a hell of a band, and it’s not a country band. Shires’ new album is straight-up nasty, grimy Southern rock, unapologetic in its heaviness. Shires even puts distortion all over her fiddle. Her voice never floats over that riffage. Instead, she’s deep in the cracks of her own songs. She sings in an electric yip, the sort of voice that Dolly Parton might’ve had if she’d devoted herself to bar-rock. Shires has the precision of a great country singer, but she never strives for beauty. Instead, she puts herself right into the desperate circumstances of her own characters.

As with Isbell, it can be tough to tell when Shires is singing from her own perspective and when she’s making up characters. She sings love-song lyrics, and they’re pointed and specific and evocative: “I envy your clothes, how they get to be so close.” It’s even more evocative when she sings about “The fear that I feel when I see my features reversed in my own daughter’s face.” (If she’s not singing about her own experiences on that song, I have to believe that she’s at least drawing on them.) “It’s OK to fall apart,” she reassures again and again on “Take On The Dark,” and she sounds like she believes it, like she feels it.

Elsewhere, though, her songs work as finely wrought short stories. That’s the case on “Eve’s Daughter,” sung from the perspective of a woman who’s always moving from town to town, chasing her bliss: “A gust of wind came blasting in the gas station where I was working / He was 23, he was out on leave, and the rest gets a little blurry.” And it’s even more true of the stunning closer “Wasn’t I Paying Attention?,” a song about a man, a recovering addict, who drives right into the center of the town of Nome, Alaska, then slits his own throat and sets his pickup truck on fire. Shires’ narrator is the guy’s friend, the one who lent him the truck. This character is very pointedly not Shires — it’s a man, for one thing — and yet Shires commits completely to his experience. It’s a hell of a piece of writing. And in its own way, it’s just as devastating as “If We Were Vampires.” The thought occurs: What if Jason Isbell has been writing so well for the last few years just because he wants to impress Amanda Shires? Because Isbell may be one of the best lyric-writers working today, but he might also be the second-best in his own family.